Lately, due to serious environmental pollution and exhaustion of fossil energy, importance of next-generation clean energy development is increasing. Among clean energy developed so far, solar cells are expected as future energy sources since the solar cell can be used semipermanently without causing environmental pollution, and solar energy resources are limitless.
A solar cell is a device for converting sunlight into electricity. However, since a thin film solar cell has low competiveness in view of cost, efficiency, etc., it is not widely used.
A representative cause of limiting the efficiency of the solar cell is the structural defect of its composition. That is, when photo-induced carriers, electrons, and holes are trapped and recombined by point defections, dislocation, stacking faults, grain boundaries, etc. in a thin film solar cell, the efficiency of the thin film solar cell becomes limited. Accordingly, if a material without such structural defects is used to manufacture a solar cell, the diffusion distances of carriers, electrons, and holes will increase, which contributes to improvement of the efficiency of a solar cell.
Accordingly, in order to overcome the above problem, a high-efficiency solar cell is needed which can be formed on a large-sized substrate having various properties, at low cost, by a simple manufacturing method.